Kitchen Extension Cost in Islington: 2026 Price Guide

Homeowners in Islington extend their kitchens more than almost anything else, and it's easy to see why once you look at the housing here - Georgian and Victorian squares and terraces around Canonbury and Barnsbury, converted warehouses near Clerkenwell, and the busy streets around Upper Street. The usual goal is simple: turn a narrow galley kitchen into a real kitchen-diner that opens onto the garden.

Typical costs

• Small extension (up to 15m²): roughly £30,000-£45,000
• Medium extension (15-25m²): roughly £45,000-£70,000
• Larger or wraparound extension (25m²+): £70,000 upwards

Treat these as a starting point rather than a quote - they assume standard building work and a reasonable-but-not-luxury fit-out. Adding bifold doors, a roof lantern or underfloor heating will push the final number up.

What affects the price locally

Access is usually what separates a straightforward Islington quote from an expensive one. Terraces without a side passage mean everything - materials in, spoil out - goes through the house, and builders price that in accordingly. Add to that the Canonbury, Barnsbury and Highbury Fields conservation areas - 42 in total, covering roughly half the borough, where matching brick, roofline and window detailing to the existing building is typically expected even for extensions that wouldn't otherwise need planning permission.

Don't overlook foundations either: much of the older housing stock close to Upper Street and Camden Passage sits on shallow Victorian or Edwardian footings, which a structural engineer will often want to deepen or extend before an extension can be signed off.

Do you need planning permission?

Many single-storey rear extensions fall under permitted development, but there are limits on how far you can extend without full planning permission, and those limits are usually tighter for terraced and semi-detached houses than detached ones. If your home is in one of Islington's conservation areas, permitted development rights can be restricted further, so it's worth checking with the London Borough of Islington's planning department - or a builder who works in the area regularly - before you commit to a design.